Carroting brush and method of carroting fur on a skin with said brush



Patented Dec. 5, 1950 UNITED STATES PATENT OFFICE CARROTING BRUSH AND METHOD OF CAR- ROTING FUR ON A SKIN WITH SAID BRUSH William Lewis Braun, Nor-walk, Conn.

No Drawing. Application February 8, 1946, Serial No. 646,495

16 Claims.

bassine, kitool, tampico and so forth, which have shown relatively poor resistance to the powerful oxidizers and acids contained in carroting solutions. A greater portion of the carroting of furs is done by hand, the solutions being applied to the fur by hand brushes, but machines have been and are now being developed for applying the carroting solution and they usually employ rotary brushes. Ordinary hand brushes made from the above fibers last anywhere from two to ten days. A further problem is encountered in rotary brushes, because instead of being merely dipped into the solution between the applications .to the fur, as in the use of hand brushes, they are continually in the solution, so that rotary brushes made from the same materials noted above last only from one to three days. It has been found that natural bristles cannot resist the action of nitric acid and peroxide for any length of time and show definite signs of breaking down after a single days operation, and after two or possibly three days are useless and have to be replaced. Not only do these natural bristles disintegrate, but after a few hours of submersion in liquid, become very soft and flexible so that they warp and lose all fatigue resistance. This is partially due to the fact that the bristles absorb several times their weight of moisture and the acid destroys the bristles. Upon drying they become very brittle so that they snap at the slightest pressure. On the other hand, if the bristles are kept .moist by submersion in water, they lose all flexing fatigue resistance and simply bend over and remain in that position.

Experiments have been made with a large number of different materials, such, for example, as nylon and other synthetic bristles, but it has been found that they, too, are unable to resist the oxidizing and chemical action of the carroting solutions, such, for example, as the nitric acid vand hydrogen peroxide commonly used. After a few hours the bristles lose their fatigue resistance and then begin to swell up and finally curl and break. The use of relatively new nonmercuriccarroting solutions has created a new problem in brushes, since they do not last more than a third of the period that the same brushes lasted when the fur cutting industry employed nitrate of mercury.

I have found by numerous experiments that synthetic resinous bristles made of the resins formed by the polymerization of certain vinyl compounds have shown most promising results. These bristles have remarkable fatigue resistance, low percentage of acid absorption (less than .25 per cent) and show no change in physical structure due to chemical breakdown after prolonged exposure to strong acids and oxidizers. I have found a plastic composition which will withstand the continuous flexing and abrasion incident to the carroting operation while saturated with strong acids suchasnitric, sulfuric, and hydrochloric, together with a strong oxidizer like hydrogen peroxide, chloric or perchloric acids, potassium persulphate, potassium permanganate, and so forth, is a synthetic resin made by the conjoint polymerization of vinyl halides with vinyl esters of the lower aliphatic acids.

The preferred proportions are about to of the vinyl halides and about mesa,-

of vinyl esters of the lower aliphatic acids. "Due to the remarkable chemical resistance of these resins, bristles made therefrom are able to withstand to a remarkable degree the continuous flexing and abrasion while saturated with the strong acids and oxidizers incident to fur carroting operations. These resins are also valuable as a material to impregnate and coat natural fibers, such as vegetable or animal bristles, so as to make them more chemical-resistant, and to impart to these natural bristles qualities whereby they can withstand the continuous flexing and abrasion while saturated with strong acids and oxidizers dur ing the carroting operation.

The preferred resins are those formed by the copolymerization of vinyl chloride with vinyl acetate. In place of the vinyl chloride any of the vinyl halides can be used and in place of the vinyl acetate any of the esters of the following group of the lower aliphatic acids may be used, namely, vinyl formate, vinyl butyrate and vinyl propionate. In either the halide group or the ester group any one or more of the group can be used. Each component gives the bristle specific characteristics, and they must be used in the proper proportions to obtain the desired resuits. The products of copolymerization of vinyl chloride with vinyl acetate containing about 80% to 95% vinyl chloride and about 5% to 20% vinyl acetate in the polymer has been found most suitable for bristles for use in the carroting of fur. with these percentage ratios a range of bristle raw material may be obtained from readily soluble to practically insoluble resins which can be plasticized to meet any requirements of flexibility. The two polymers, vinyl chloride and vinyl acetate, would neither have the required acid resistance when used alone, but I have found that when used as copolymers in the proportions named the resulting resins have very material increased acid resistance, resilience and elasticity.

As the percentage of plasticizer is increased, the resin changes from a hard horny material to a soft and thermoplastic mass. The most common plasticizers used are tricresyl phosphate, dibutyl phthalate or dioctyl phthalates. Upon the use of the proper plasticizer depends the characteristic of the resin, such as tensile strength, processibility and thermoplastic temperature range. The copolymer can be made to differ in physical and chemical properties by altering the percentage of vinyl acetate and the extent of polymerization. The resins used in stiff bristles, such as are required for carroting furs, are those with a high percentage of vinyl chloride and of high molecular weight (10,000 to 25,000, as determined by the Staudinger viscosity method). These resins have excellent chemical resistance. They are characterized by their toughness, elasticity, low temperature flexibility, non-flammability, good abrasion resistance, and most important from the viewpoint of use as bristles for fur carroting brushes, a long flexing fatigue resistance. They are also good carriers of the solution.

Following are certain examples which are given by way of illustration, but are not to be construed as indicating the bristles are to be limited thereto. These are preparations which will yield a very stifi fiber, possessing good resilience, excellent fatigue resistance, toughness, very low moisture absorption, and good resistance to abrasion:

Example 1 Copolymer of: Percent Vinyl chloride 90 92 Vinyl acetate 5 5 Dibutyl phthalate 5 3 Example 2 Copolymer of Vinyl chloride 88 Vinyl acetate Tricresyl phosphate 2 Example 3 Cc polymer of Vinyl chloride 80 85 90 Vinyl acetate.- 20 10 The vinyl chloride gives hardness and stiffness or brittleness, while the vinyl acetate gives toughness and resilience. By varying the relative proportions of these ingredients, the characteristics of the bristles may be varied accordingly to meet any conditions and requirements as to flexibility and so forth. Thus, in the third example given, the proportion of vinyl chloride (which imparts hardness and stiffness) is so low that no plasticizer is needed.

One way of fabricating the bristle is to extrude it through a heated die or nozzle, and after leaving this nozzle it is stretched to more than twice its original length. This stretching brings the molecules previously arranged in helter-skelter fashion, parallel to one another and in closer union with each other. Such a realignment causes an increase in molecular cohesion and tensile strength, and also greater pliability and flex resistance is obtained. These materials are thermoplastic, but as the carroting processes are all cold processes, or that is, are carried on at room temperatures, the solu tion temperature is usually around 70 F. and the bristles retain their form, rigidity, resilience and other desired characteristics.

Subsequent to this elongation the fiber may again be heated and allowed to shrink from 5% to 25%. The heating and stretching aligns the molecules of the plastic in a linear chain, giving the fiber unusual strength and hardness, while the subsequent shrinkage gives the flber the necessary elasticity and flexibility, which prevents the filament from breaking when sharply bent, as is necessary in making the bristles into brushes.

In the coating and impregnating of natural fibers, either animal or vegetable, for example, ordinary vegetable fibers such as kitool, bassine and so forth, with Vinylite copolymer resins, this can be done by dissolving the granular or powdered resin, such as, for example, a copolymer of vinyl acetate and vinyl chloride as above described, in a suitable solvent, such, for example, as one composed of 15% 2-nitropropane and 85% toluol or other suitable medium. For

coating, a solution containing 15% of the solid.

resin produces satisfactory results. For impregnating under pressure, a lighter solution, such, for example as from 5% to 10% of the solid resin, produces better results.

Any of the various forms of brushes commonly used for carroting operations, both in hand carroting and machine carroting, may be used and the bristles mounted in their supports by any suitable and known methods of mountin the bristles to form the brushes.

While this description has stressed certain definite compositions, it is to be understood that it is possible to make many modifications by those skilled in the art. The compositions described have been found to have very novel and improved characteristics and qualities, particularly in their use in making bristles for brushes employed in the fur carroting process.

Having thus set forth the nature of my invention, what I claim is:

l. A brush comprising bristles of sufl'icient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of vinyl chloride and vinyl acetate.

2. A brush comprising bristles of sufficient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of from to vinyl chloride and 5% to 20% vinyl acetate.

3. A brush comprising bristles of sumcient strength and stiffness combined with flexibility "resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower "aliphatic acid.

4. A brush comprising bristles of suflicient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise essentially a vinyl resin resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid and containing from 80% -to 95% of the vinyl halide in the copolymer.

5. A cylindrical rotary brush comprising bristles of suflicient strength nad stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin Without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of vinyl chloride and vinyl acetate.

6. A cylindrical rotary brush comprising bristles of suflicient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid.

1 8. A cylindrical rotary brush comprising bristles of sufficient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into fur on a skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise essentially a vinyl resin resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid and containing from 80% to 95% of the vinyl halide in the copolymer.

9. A method of carroting fur on a skin with a brush comprising bristles of sufficient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of vinyl chloride and vinyl acetate.

10. A method of carroting fur on a skin with a brush comprising bristles ofv sufficient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of from 80% to 95% vinyl chlo ride and 5% to 20% vinyl acetate.

11. A method of carroting fur on a skin with a brush comprising bristles of suflicient strength and stiflness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid.

12- A method of carroting fur on a skin with a brush comprising bristles of suflicient strength and stiffness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise essentially a vinyl resin resulting from the conjoint polymerization of a vinyl halide with .,a vinyl ester of a lower aliphatic acid and containing from to of the vinyl halide in the copolymer.

a cylindrical rotary brush comprising bristles of suflicient strength and stiflfness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of vinyl chloride and vinyl acetate.

14. A method of carroting fur on a skin with a cylindrical rotary brush comprising bristles of sufiicient strength and stiifness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise a vinyl resin which is a copolymer of from 80% to 95% vinyl chloride and 5% to 20% vinyl acetate.

15. A method of carroting fur on a skin with a cylindrical rotary brush comprising bristles of sufllcient strength and stiffness combined with flexibility to apply a carroting'solution to and brush it into the fur on a skin without tearing the fur from the skin, which bristles also have tion under the action of carroting solutions. and

16. A method of carroting fur on a skin with a 5 cylindrical rotary brush comprising bristles of sumcient strength and stiifness combined with flexibility to apply a carroting solution to and brush it into the fur on a skin, which bristles also have the characteristic of high resistance to deterioration under the action of carroting solutions, and which bristles are of substantially uniform composition throughout and comprise essentially a vinyl resin resulting from the conjoint polymerization of a vinyl halide with a vinyl ester of a lower aliphatic acid and containing from 80% to 95% of the vinyl halide in the copolymer.

WILLIAM LEWIS BRAUN.

8 REFERENCES cm The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 430,077 Jenness June 10, 1890 1,882,439 Murphy Oct. 11. 1932 2,015,103 Dreyfus Sept. 24, 1935 2,161,766 Rugeley June 6, 1939 2,207,158 Neville July 9, 1940 2,230,358 Mason Feb. 4, 1941 2,234,813 Tomaino Mar. 11, 1941 2,341,823 Smith Feb. 15. 1944 2,352,740 Shannon July 4, 1944 2,433,325 slaughter Dec. 23, 194'! 

1. A BRUSH COMPRISING BRISTLES OF SUFFICIENT STRENGTH AND STIFFNESS COMBINED WITH FLEXIBILITY TO APPLY A CARROTING SOLUTION TO AND BRUSH IT INTO FUR ON A SKIN WITHOUT TEARING THE FUR FROM THE SKIN, WHICH BRISTLES ALSO HAVE THE CHARACTERISTIC OF HIGH RESISTANCE TO DETERIORATION UNDER THE ACTION OF CAROTING SOLUTIONS, AND WHICH BRISTLES ARE OF SUBSTANTIALLY UNIFORM COMPOSITION THROUGHOUT AND COPRISE A VINYL RESIN WHICH IS A COPOLYMER OF VINYL CHLORIDE AND VINYL ACETATE.
 9. A METHOD OF CARROTING FUR ON A SKIN WITH A BRUSH COMPRISING BRISTLES OF SUFFICIENT STRENGTH AND STIFFNESS COMBINED WITH FLEXIBILITY TO APPLY A CARROTING SOLUTION TO AND BRUSH IT INTO THE FUR ON A SKIN WITHOUT TEARING THE FUR FROM THE SKIN, WHICH BRISTLES ALSO HAV ETHE CHARACTERISTIC OF HIGH RESISTANCE TO DETERIORATION UNDER THE ACTION OF CARROTING SOLUTIONS, AND WHICH BRISTLES ARE OF SUBSTANTIALLY UNIFORM COMPOSITION THROUGH OUT AND COMPRISE A VINYL RESIN WHICH S A COPOLYMER OF VINYL CHLORIDE AND VINYL ACETATE. 